Origin of the oldest (3600–3200 Ma) cratonic core in the Western Dharwar Craton, Southern India: Implications for evolving tectonics of the Archean Earth - Université Clermont Auvergne Access content directly
Journal Articles Earth-Science Reviews Year : 2023

Origin of the oldest (3600–3200 Ma) cratonic core in the Western Dharwar Craton, Southern India: Implications for evolving tectonics of the Archean Earth

Abstract

This contribution presents a comprehensive synthesis on the origin of oldest (3600–3200 Ma) cratonic core in the Western Dharwar Craton (WDC), Southern India based our new field, geochronologic, elemental and Nd-Hf isotopes data on the Holenarsipur greenstone belt and adjacent granitoids combined with published record on the stratigraphically equivalent greenstone belts in the same region. Our study shows that the oldest cratonic core in the WDC formed through assembly of different tectonic units close to 3200 Ma. These tectonic units include microcontinental remnants with oceanic plateaus, oceanic island arcs and preserved oceanic crust similar to modern oceanic crustal section close to a spreading center. Isotopic age data for these greenstone sequences (detrital zircons -ca.3600–3230 Ma; volcanics 3384–3200 Ma) and adjoining granitoids (3430–3400 and 3350–3270 Ma with remnants of older 3600–3500 Ma gneisses) indicate that a large part of the old TTG-type granitoids in the WDC is either coeval to or slightly younger than associated greenstone units. The final stage of assembly of these tectonic elements into cratonic framework through horizontal motion of intervening oceanic crust and eventual slab breakoff is marked by the formation of ca. 3200 Ma trondhjemite magmas, emplacement of which into the lower crust caused partial convective overturn of the crust, thereby leading to the development of dome and keel patterns followed by metamorphism and cratonization of the WDC crust at 3100 Ma. Our study strongly suggests that the tectonic environments in which Archean cratons formed require some sort of horizontal motion but not necessarily modern plate tectonics. However, vertical addition of juvenile crust in hotspot environments associated with mantle plumes played a major role in building of early crustal nuclei. The model proposed for the formation of the cratonic core in the western Dharwar craton is compatible with observations made globally in most of the Paleoarchean craton.
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hal-04012947 , version 1 (23-09-2023)

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Attribution - NonCommercial - NoDerivatives

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M. Jayananda, Martin Guitreau, K.R. Aadhiseshan, T. Miyazaki, S.L. Chung. Origin of the oldest (3600–3200 Ma) cratonic core in the Western Dharwar Craton, Southern India: Implications for evolving tectonics of the Archean Earth. Earth-Science Reviews, 2023, 236, pp.104278. ⟨10.1016/j.earscirev.2022.104278⟩. ⟨hal-04012947⟩
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